1. Field of the Invention
The present invention relates to a cylinder valve assembly which is attached to a cylinder storing compressed gas, liquefied gas and the like, and more particularly to a cylinder valve assembly with a check valve, which internally houses the check valve so as to prevent reversely flowing gas, gas of a different kind, gas containing impurities and the like from flowing into a cylinder and besides to inhibit air, rain drops or the like foreign matters from entering the cylinder with the result of decreasing the purity of the stored gas.
2. Explanation of Related Art
The cylinder valve assembly with the check valve of this type comprises a housing within which an inlet bore communicates with an outlet bore through an inlet passage, a stop valve chamber, a check valve seat and a check valve chamber in the mentioned order. A check valve member is inserted into the check valve chamber and is resiliently pushed by a check spring for closing with respect to the check valve seat.
When the cylinder has an inner pressure not less than a set one, a stop valve within the stop valve chamber is opened, thereby enabling gas pressure acting on a valve face of the check valve member to open the check valve member against a valve closing force of the check spring. This results in taking gas out of the cylinder. On the other hand, when the cylinder has a residual pressure lowered to the set one, the valve closing force of the check spring overcomes the gas pressure acting on the valve face to close the check valve member. This maintains a predetermined residual pressure within the cylinder and therefore prevents invasion of foreign matters and the like from an exterior area. In the event that there comes from the outlet bore, reversely flowing gas which contains impurities residual in various instruments, is of a different kind or the like, the reversely flowing gas has a pressure cooperating with the check spring to close the check valve member.
Meanwhile, the cylinder valve assembly internally houses the foregoing check valve. Therefore, when recharging gas from the outlet bore into the cylinder, it is required to forcedly open the check valve member so as not to close the check valve member with a charging pressure. In this case, if the check valve member can be readily opened at a place other than the place where a predetermined charging system is installed, there is a likelihood that the gas which contains impurities or is of a different kind is readily charged to contaminate an interior area of the cylinder. Thus the above-mentioned check valve member is desirably constructed so that it can be opened by using a special system or a jig.
Japanese Patent Public Disclosure No. 3-20199 proposed earlier by the present Assignee recites a conventional example of the cylinder valve assembly with the check valve which can be forcedly opened when charging gas.
The conventional example forms a valve-opening means accommodation portion at a position where a check valve member faces the accommodation portion through an inlet of a check valve chamber. Attached in the valve-opening means accommodation portion is a check valve member opening means. The opening means switches over from a valve opening position where it advances to the check valve chamber and pushes the check valve member for opening it, and a valve-opening cancellation position where it retreats from the check valve chamber and separates from the check valve member. The check valve member has an input portion formed from a piston of fluid-pressure actuation type. A valve-opening actuation chamber is formed between the piston-type input portion and a rear end wall of the valve-opening means accommodation portion. The rear end wall is formed with an input hole which comprises a flow passage of pressurized fluid. The valve-opening actuation chamber communicates with an external portion of the valve-opening means accommodation portion through the input hole. The check valve member opening means is retained at the valve-opening cancellation position by a valve-opening cancellation spring so as not to open the check valve member by mistake at the time other than the time of charging. Further, the input hole composed of the flow passage is inclined with respect to an axis of the input portion of the check valve member opening means in order that such opening means might not be pushed by some other thing.
When charging gas into the cylinder, a charging means is connected to the outlet bore of the cylinder valve assembly and a source of pressurized fluid such as compressed air is connected to the input hole provided in the rear wall of the valve-opening means accommodation portion. Then the pressurized fluid is introduced into the valve-opening actuation chamber to move the check valve member opening means to a valve opening position. After having opened the check valve member, the stop valve is opened to charge gas from the outlet bore into the cylinder.
The conventional cylinder valve assembly with the check valve is excellent in that it can be easily opened by using a special system and a jig and besides the check valve member cannot be opened at a place other than the place where these predetermined charging systems are installed and that it can prevent the interior area of the cylinder from being contaminated by charging the gas which contains impurities, is of a different kind and the like. However, the conventional technique has to be still improved on the following points:
(1) It moves the check valve member opening means with the pressurized fluid and therefore requires to provide in the charging device a source of pressurized fluid such as compressed air. In addition, for example, a flow passage must be formed so as to connect the source of pressurized fluid to the input hole in communication therewith. This increases the number of parts to result in inviting a problem that it cannot be put into practice inexpensively;
(2) Instead of the foregoing construction that the check valve member opening means is moved with the pressurized fluid, it can be considered to mechanically move the check valve member opening means. However, a protecting means must be provided in order that the check valve member opening means might not be pushed by some other thing by mistake at the time other than the time of charging. Besides, the valve-opening actuation means has to adopt such a complicated structure as a cam mechanism in order to be able to move the check valve member opening means while cancelling the protecting means. This increases the number of parts to be needed with the result of entailing the problem that the conventional technique cannot be put into practice inexpensively.
The present invention has an object to provide a cylinder valve assembly with a check valve which can prevent gas from being charged at a place other than the place where a predetermined charging system is installed but can charge gas by using an existing charging device as it is at the place where the predetermined charging system is installed and besides can be put into practice with a simple structure inexpensively.
In order to accomplish the above object, the present invention has constructed a cylinder valve assembly with a check valve in the following manner, for example, as shown in FIGS. 1 to 5.
A housing 4 is formed with an inlet bore 7, a stop valve chamber 9, a check valve chamber 41 and a valve-opening means accommodation portion 53. The check valve chamber 41 is provided with a check spring 43 and a chamber inlet 41a which communicates with the inlet bore 7 through the stop valve chamber 9. A check valve seat 44 is formed around the chamber inlet 41a. A check valve member 42 is inserted into the check valve chamber 41 and is resiliently pushed by the check spring 43 to the check valve seat 44. The valve-opening means accommodation portion 53 has a peripheral wall and is formed at a position where it faces the check valve member 42 through the chamber inlet 41a. A check valve member opening means 51 is attached in the valve-opening means accommodation portion 53. The opening means 51 is pushed by a valve-opening actuation member 60 to switch over to a valve opening position (Y) where the opening means 51 advances toward the check valve chamber 41 and pushes the check valve member 42 for opening. It is released from a pushing force of the valve-opening actuation member 60 to switch over to a valve-opening cancellation position (X) where it retreats from the check valve chamber 41 and separates from the check valve member 42. A lock means 55 made of a magnetic body is attached between the peripheral wall of the valve-opening means accommodation portion 53 and the check valve member opening means 51. This lock means 55 changes over between a lock position (L) where it limits an advancement of the check valve member opening means 51 from the valve-opening cancellation position (X) and a lock cancellation position (M) where it allows this advancement. The valve-opening actuation means 60 is provided with a lock cancellation means 61 made of a magnetic body. At least one of the lock means 55 and the lock cancellation means 61 is formed from a magnet. There occurs between the lock means 55 and the lock cancellation means 60 a magnetic force, which changes over the lock means 55 from the lock position (L) to the lock cancellation position (M).
The present invention functions as follows.
When taking out gas or storing it, the check valve member opening means is arranged at the valve-opening cancellation position and the lock means exists at the lock position. This prevents the check valve member opening means from moving to the valve opening position even if some other thing collides with the check valve member opening means and pushes it erroneously. Accordingly, there is no likelihood that the check valve member inadvertently opens.
When charging gas, if the valve-opening actuation means with the lock cancellation means is attached to a predetermined position, the lock means changes over to the lock cancellation position by the magnetic force occurring between the lock cancellation means and the lock means. Subsequently, when the valve-opening actuation means pushes the lock means as it remains at the lock cancellation position, the check valve member opening means moves to the valve opening position to push the check valve member for forced opening. This charges the gas from the charging device into the cylinder through the outlet bore, the check valve chamber, the stop valve chamber and the inlet bore in the mentioned order.
It is possible to form either of the lock means and the lock cancellation means from a magnet. However, in general, since the housing and the like is formed from a magnetic body, preferably, the lock means is not formed from a magnet but the lock cancellation means is made of a magnet. The lock cancellation means is not necessarily formed integral with the valve-opening actuation means. However, in the case where both are formed integral with each other, a sequential operation can perform the switch-over of the lock means to the lock cancellation position by the lock cancellation means as well as the movement of the check valve member opening means to the valve opening position by the valve-opening actuation means. Therefore, this case is more preferable.
The present invention is constructed and functions as mentioned above, and therefore offers the following advantages.
The lock means changes over to the lock cancellation position only by attaching the valve-opening actuation means to the predetermined position. If the valve-opening actuation means pushes the check valve member opening means with the lock means remaining at the lock cancellation position, the check valve member can be opened. Therefore, the valve-opening actuation can be performed with a simple construction. Additionally, it suffices if the lock means is made of a magnetic body and the valve-opening actuation means is provided with a lock cancellation means formed from a magnetic body. This reduces the number of parts, simplifies the structure and besides gets rid of the necessity to provide any additional system in the charging device with the result of being able to put the present invention into practice inexpensively.
The present invention includes the following cylinder valve assembly with a check valve.
The lock cancellation means 61 is made of a magnet and is disposed on a leading end portion of the valve-opening actuation means 60, which end portion faces the check valve member opening means 51. In this case, the present invention is applicable to a common cylinder valve assembly having a housing 4 formed from a cast iron or the like magnetic body. Besides, when the valve-opening actuation means 60 has its leading end brought into contact with a rear end portion of the check valve member opening means 51 to change over the lock means 55 to the lock cancellation position (M) and push it as it is, the check valve member opening means 51 can be moved to the valve opening position (Y). Thus only an extremely simple operation is sufficient.
The check valve member opening means 51 has an outer peripheral surface formed with an annular lock means accommodation groove 54. On the other hand, the valve-opening means accommodation portion 53 has a peripheral wall formed with an engaging groove 59 at a position where the lock means accommodation groove 54 opposes to the engaging groove 59 when the check valve member opening means 51 comes to the valve-opening cancellation position (X). And the lock means 55 is made spherical and accommodated in the accommodation groove 54. The lock means 55 partly invades the engaging groove 59 and comes to the lock position (L). In this case, the lock means 55 comprises at least one steel ball or the like and besides changes over to the lock position (L) owing to the action of gravity. This reduces the number of parts with the result of being able to put the present invention into practice inexpensively with a simple construction.
Preferably, the lock means accommodation groove 54 is formed wider as it opens more outwardly and has its side walls inclined. This makes it possible to change over the lock means 55 to the lock position (L) through the action of gravity even if the check valve member 42 or the check valve member opening means 51 is arranged in any direction.
More preferably, the check valve member opening means 51 has its rear end concaved to provide an attaching recess 51a, to which the valve-opening actuation means 60 has its leading end attached. This enables the magnetic force of the lock cancellation means 61 disposed on the leading end portion of the valve-opening actuation means 60 to readily act on the lock means 55.
Still more preferably, the valve-opening means accommodation portion 53 is provided with a valve-opening cancellation spring 56. The spring 56 resiliently pushes the check valve member opening means 51 from the valve opening position (Y) to the valve-opening cancellation position (X). Thus the check valve member opening means 51 moves from the valve opening position (Y) to the valve-opening cancellation position (X) by an urging force of the spring 56, upon removal of the pushing force of the valve-opening actuation means 60, which results in releasing the check valve member 42 from the forced opening condition.